A dilator is a tool or device that is used to expand or widen a particular part of the body. It helps to make an opening or passage larger, allowing for easier access or movement. Full definition
After three pregnancies, however, I've found that a carefully applied nasal dilator strip stops my most egregious snoring and makes it easier for me to fall asleep after a bathroom trip — minus all the honking and sniffling. (health.com)